Alarm device



April 25, 1939. F. BRINKMANN ALARM DEVI C E Fild May 6, 1936 ffzvezz for h M m n r aw m MW 5 Patented Apr. 25, 1939 UNITED STATES ALARM DEVICE Friedrich Brinkmann,

Germany,

Berlin- Charlottenburg,

assignor to C. Lorenz Aktiengesellschaft, Berlin-Tempelhof, Germany, a com- Application May 6, 1936, Serial No. 78,193 In Germany May 10, 1935 6 Claims.

The invention relates to alarm devices of the kind having a member adapted to be displaced therein in order to indicate by its position whether the device is in normal or in operative condition. More particularly the invention refers to devices of this type wherein a solder holds the indicating member in its position of rest, so that such member on the solder melting is released in order to assume its position of alarm. In known devices the indication member is springpressed.

The novel device is so designed that the indicating member shall assume its alarm position by gravitation. As a result, devices of this kind can be made to be very simple and reliable and can further be arranged to indicate the alarm position in a striking manner, whilst a simple manipulation will be sufficient to restore them to normal after having been actuated. In this connection a novel construction of the solder or fusible body will be advantageous, that is, a construction which does not require special tools to be used when fitting the fusible body to the parts to be attached to each other.

One embodiment of the invention is represented in the accompanying drawing in which Fig. 1 shows a vertical section through the device with the movable parts thereof in normal condition. Fig. 2 is a partially sectioned elevation thereof, offset at right angles with respect to Fig. l, the device here being likewise in normal condition. Fig. 3 is an end view of the fusible body, Fig. 4 a side view thereof. Fig. 5 is a view similar to Fig. 1 but showing the parts released.

In a socket a of a tubular casing btwo fiat springs d, e are fixed. These are hook-shaped at their lower ends in order to engage annular grooves n of a heat-responsive means or fusible body 1 which then acts as a sort of clamp to hold the free ends of the springs together, as will be seen in Figs. 1 and 2. The springs while in this position are supporting a hollow cylinder by grasping a cross bar g thereof. Cylinder c, which serves as an indicating member, is at that time completely enclosed by the casing b. Cylinder c has a flange p. Casing b is fitted with a rib r. Fixed in the socket a is also an arm 2' that in conjunction with spring at forms a contact is. The device may thus serve for instance for the supervision of a circuit wherein the parts e, f, d are included.

The fusible body on melting releases the springs d, e. These therefore take up the position shown in Fig. soas to allow cylinder 0 to drop into the position represented in Fig. 5,

in which said tubular in which flange p is resting upon rib r. When in this position the cylinder 0 projects through the lower opening of the casing b, thus indicat ing that the device has become active. Contact is may serve for closing an alarm circuit.

In order to restore the released parts to normal it is only necessary to move cylinder 0 upward and to insert a new fusible body 1 over the springs d, e. An efficient contact between the parts d, e, I may be established by pressing them against each other.

The socket a carries a resistance coil 8 which becomes active on the release of the alarm device.

Apertures q of the casing b enable the heat ascending in the parts 0, b to escape therefrom.

The casing b, a may be made of insulating material by a squirting process.

What is claimed is:

l. A fire alarm fuse box comprising a vertically disposed shell open at its lower end, a tubular member contained in said shell, a cross bar within this tubular member and rigid therewith, contact springs projecting into said tubular member through the upper end thereof, a fusible body inserted over the free ends of the contact springs to hold said ends together, the contact springs embracing the said cross bar so as to support said tubular member, a stationary contact, one of said contact springs having a normal tendency to move towards said stationary contact and being normally held from engagement therewith by said fusible body, the free ends of said spring supporting said tubular member within the shell against gravity.

2. A fire alarm fuse box according to claim 1 member drops freely under control of gravity in response to melting of said fusible body to provide a visible exterior indication.

3. A fuse box accordng to claim 1 in which said fusible body engages the ends of the springs so as to tension them towards each other while maintaining the said ends in fixed spaced relation.

4. A fuse box according to claim. 1 in which the said fusible body has grooves to engage the said free ends of the contact springs.

5. A fuse box according to claim 1 wherein the fusible body is in the shape of a cylindrical plug having spaced annular circumferential grooves to engage the ends of the contact springs.

6. A fuse box according to claim 1 wherein the fusible body has grooves and the ends of said contact springs are hook-shaped to embrace said fusible body around said grooves.

FRIEDRICH BRINKMANN. 

